You will need at least an _ACS_ release 3 to acheive the different ring times. You will then be able to set the VMS Hunt Delay on a per line basis.
But as long as you have a Partner II, and you just want your "backdoor" lines for family/employees/special clients to be answered immediatly, why don't you use DXD for lines 5 and 6? DXD gives you up to a 20 second message, and then waits for the caller to input an extension number. Just assign the lines to DXD instead of Call Dist. Group 7, set it to 0 rings, put a DXD button on Ext. 10 and tell them to always leave it on. Set the lines to delayed ring so you don't hear them ring in, but you get some type of alert if someone turns DXD off. Record the DXD message from Ext. 10 or 11 with Intercom 892.